Following the onset of hostilities during World War I, non-naturalized "Enemy Aliens" by definition, were required to register with United States authorities as a national security measure. Under the provisions of a Presidential Proclamation of April 6, 1917, non-naturalized female aliens were likewise registered as an additional national security measure that included those women of American birth that were married to enemy aliens. For the State of Kansas the registered aliens represent a broad cross-section of the German-born population of the State. The series contains original affidavits of registration that record personal information about each registrant, their photograph affixed to the majority of documents, and the registrants fingerprints.

This information was obtained using a NAIL search at the website of the National Archives and Record Administration. Copies of the original affidavits are available from NARA; for instructions on how to obtain these, please visit their website.